[a3_nm]

Maybe the relevant section is left over from the previous license, which was CC-BY-NC (http://blog.mapillary.com/update/2014/03/17/mapillary-goes-c...). Alternatively, IANAL but I imagine that the individual photos could still be CC-BY-SA (if, e.g., someone else redistributes them) but that the service itself cannot be used for commercial purposes. As bulk exports are prohibited (2.1) and dumps are not provided, however, this would mean that the data is CC-BY-SA in theory but hard to reuse commercially except for individual pictures.

[Doctor_Fegg]

The crucial information is the lat/long of each photo. If that's not licensed openly (and, as metadata, CC0 or ODbL would be better suited than CC-BY-SA) then it's just a nice collection of photos.

[pmontra]

Exactly. I can't see me contributing to this if I can't be sure I'll be able to get all the pictures with all their metadata. There have been enough services built thanks to user contributions that closed their data later on. I think we deserve guarantees that this isn't going to happen.